244 HEMIPTERA-HOMOPTEEA. 



attacks all fruit-trees and numbers of other deciduate trees and 

 various plants. One female has been shown to account for 

 3,216,080,400 young in the year under favourable conditions 

 (Lintner). Numbers of species are injurious in our hothouses, 

 such as the Greedy-scale (A. camellice) and the Oleander-scale 

 (A. nerii), but out of doors only two or three ever do much harm. 

 The most prevalent is the Mussel-scale (^Mytilaspis jiomorum) on 

 apple and pear, the Brown-soale(LeMcaraiM??iri&t.s), and the Woolly 

 Currant-scale (Pulvinia i-ihesii), the second on gooseberry and 

 currants, the last on currants and Pyracanthus. 



The Mussel-scale {Alytilaspis pomwwn). 



This scale belongs to the genus Mytilaspis, aU of which are 

 elongated scales, mussel-like in form. The mussel-scale is 

 brown, from -^ to -g- of an inch long, and of nearly uniform 

 width except in the front, where it tapers to a point. Some- 

 times the scales are straight, at others curved. The eggs are 

 creamy -white, and may number between eighty and ninety, 

 being scattered about under the scale : we find them in the 

 winter. There is only one brood : the young six-legged larYse 

 (fig. 124, iv) appear in the late spring, and soon settle down to 

 form fresh scales. The male scales (vi) are much smaller than 

 the female (v). It is a widespread insect, occurring in America, 

 in Australia, and in S. Africa. 



This, like all scale insects, is spread from tree to tree and 

 orchard to orchard by the wind, and on the feet of birds and 

 the back of insects. It has been noticed that some scale-larvs 

 prefer the back of dark-coloured beetles. Youug apple-trees 

 suffer severely from this pest in Britain, and should be 

 thoroughly cleaned before being planted. 



Prevention and Remedies. — Scale insects are often difficult to 

 destroy. Fumigation of young stock with hydro-cyanic acid 

 gas and the application of resin washes are the most successful 



